Pelvic inflammatory disease and the risk of ovarian cancer: a meta-analysis

Abstract

Purpose: Previous studies on pelvic inflammatory disease (PID) and the risk of ovarian cancer have found inconsistent results. We performed an updated meta-analysis to summarize the evidence of this association. Methods: PubMed, Embase, and ISI web of science databases were searched through October 2016 for studies that investigated the PID and ovarian cancer association. Summary risk estimates were calculated using random-effects meta-analysis. Result: Thirteen studies were eligible for analysis, which included six cohort studies and seven case–control studies. PID was associated with an increased risk of ovarian cancer overall [relative risk (RR) 1.24, 95% CI 1.06–1.44; I2 = 58.8%]. In analyses stratified by race, a significant positive association was observed in studies conducted among Asian women (RR 1.69, 95% CI 1.22–2.34; I2 = 0%), but marginally significant among Caucasians (RR 1.18, 95% CI 1.00–1.39; I2 = 60.7%).Risk estimates were elevated in both cohort (RR1.32; 95% CI 1.05–1.66; I2 = 64.7%) and case-control studies (RR 1.17; 95% CI 0.93–1.49; I2 = 57.6%), albeit not statistically significant in case–control studies. Conclusions: Our results suggested that PID might be a potential risk factor of ovarian cancer, with pronounced associations among Asian women. Large and well-designed studies with objective assessment methods, such as hospital records, are needed to confirm the findings of this meta-analysis.